Portable grinding tool



July 19, 1927.

E. A. HALL PORTABLE GRINDING TOOL Filed Max ch s. 1924 7 /b; v H E E /7 gwwnkoz Q M Patented July 19, 1927.

UNITED STATES ERNEST A. HALL, 0]? TOLEDO, OHIO.

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Application filed March 5, 1924. Serial No. 696,924.

, This invention relates more particularly to portable tools for grinding the valve seats of internal combustion engines of the poppet-valve type, and has for one of its objects the provision of an easily operable and simple and highly eflicient tool of this character, whereby to enhance the practicability and commercial value thereof. Another object of the invention is the provision of a tool of this character, the grinding member of which is adjustable with respect to the valve seat to limit the grinding action as desired.

Other objects and advantages of the invention will be apparent from the following detailed description.

While the invention in its broader aspect is capable ofembodiment in numerous forms, a preferred embodiment thereof is illustrated in the accompanying drawings, in which,; I

Figure "1 is a central longitudinal sectional view of a tool embodying the invention with parts in full and mounted in slightly spaced operative relation to a valve seat of an engine cylinder, the cylinder being fragmentarily shown, and Fig. 2 is a similar view with parts of the tool in full and with the gauge means disconnected from the tool frame. Referrin to the drawings, 1 designates an engine cyllnder with the head-cap thereof removed to render the valve seats accessible for grinding, one of which seats is shown and designated 2. Below the valve seat, coaxial therewith, is provided the customary valve stem hearing, which, in the present instance, is formed by the bushing 3.

The tool embodying the invention includes a support or pilot member 4, which comprises a stem adapted to be fitted at its lower end down intothe valve stem bearing 3, whereby it is supported in true centered relation to the valve seat 2, the upper end of the stem being projected a distance above the valve seat, as shown. It is preferable to taper the upper end of the portion of the stem which fits into the bearing 3 so it will closely fit and center itself in the hearing, if any wear is present therein.

The tool proper, separate from the support 4, includes, in its present embodiment, a sleeve or hollow shaft 5 adapted to fit. at its lower end down over the upper pro ecting end'of the stemc4, whereby the sleeve is centered with respect to the valve seat, and the upper end of such sleeve projects axlally through an electric motor 6, being threaded or otherwise suitably fixed at its upper free end to the upper hub portion 7 of the motor frame. The motor armature 6 is mounted on the upper end portion of a hollow shaft 8, which shaft freely encircles the sleeve 5 preferably free from contact therewith, exceptat its lower end where it engages a suitable bearing 9 on the lower end of the sleeve, the shaft 8 having upper and lower ball bearings 10 in the upper and lower ends of the motor "frame orcasing to center it at such end with respect to the sleeve 5. It is thus evident that the motor frame and sleeve 5 remain stationary and that the armature shaft 8 alone has rotation during a running of the motor.

The lower end of the armature or motor shaft 8 is provided with a grinding or abrading wheel 11, having a surface conforming to the surface of the valve seat or part to be ground.

The hub portion 7 of the motor frame is provided at its upper or outer end with a threaded socket 12 co-axial with the motor axis, and a plug 13 is threaded in such socket for axial adjusting movements relative to the motor. The plug 13 has an annular flange 14 at its outer end to facilitate a hand turning of the same, and is provided in such end with an axially disposed threaded socket 15, the bottom of which is formed with a tapered or conical seat 16. A clamping sleeve 17 is threaded into the plug 13, and the lower end of this sleeve is split to permit a contraction thereof when the sleeve is screwed down against the taper 16 of the plug. A control rod 18- projects axially through the sleeve 17, plug 13 and down into the sleeve 5 in position to abut at its lower end against the upper endof the supporting stem 4 and is secured in adjusted position with respect to the members 13 and 17 by a screwing home of the latter, which effects a firm clamping of the split or clutch end of the member 17 to the rod. When the rod 18 is thus clamped to the member 13, it may be-moved up and down within the sleeve 5 by a turning of the member 13 in the socket 12 of the motor frame. It is evident that when the control rod 18 is resting on the su port 4 and the control-member 13 is turns down into the socket 12, the motor 6, armature shaft 8 and grinding member 11 will be raised relative to the support 4 and valve seat 2.

In the use of my tool, in grinding a valve seat, the support 4 is placed in a valve stem bearing 3 of a cylinder, the valve of the seat to be ground, having been previously removed, the stem 4 in such position projecting up through the valve seat opening in concentric relation thereto and a distance above the same. The grinding tool is then placed with the lower end of its frame sleeve or hollow standard 5 fitting down over the stem 4 and with the grinding wheel 11 rest-' ing on the valve seat 2 to be ground. The clamping nut 17 for the control rod 18 having previously been released from said rod. so as to permit the rod to adjust itself to the extent of projection ofthe stem 4 into the sleeve 5, or, in other words, so that the lower end of the rod will be permitted to rest freely on the standard 4, the nut 17 is then tightened to clamp the rod to the control member 13. The operator then turns the control member 13 down a short distance into the motor frame socket 12 to effect a raising of the motor frame shaft 8 and grinding wheel 11 sufiiciently to withdraw the grinding wheel from contact with the valve seat. The motor is then started to effect a driving of the grinding wheel and the operator slowly turns the control member 13 up to permit the grinding wheel to gradually move into grinding engagement with the valve seat and to grind the same the desired extent. At any time during the grinding, the tool may be easily and quickly lifted from engagement with the valve seat and supporting rod 4 to permit inspection of the seat.

It is evident that in the use of my tool, the stem 4 serves to retain the grinding wheel at all times in concentric relation to the valve seat, being mounted to support the tool and its grinding wheel in desired relation to the valve seat, and that the adjust-v able control rod 18 meets with the stem 4 to support the tool and to permit a very fine and accurate adjustment of the same with respect to the work.

It is also evident that my a hollow driven shaft carrying an abrading member and having means disposed therein and projecting therefrom to permit a manual holding of the tool and for centering the abrwding member with respect to the work,

, andthat while I have shown the drive shaft for the abrading member as driven by a directly connected electric motor, it may be driven in any other suitable manner.

I wish it understood that my invention is not limited to any specific construction, arrangement or form of parts as it is capable of-numerous modifications and changes without departing from the spirit of the claims.

tool embodies I claim as new and desire to secure by Letters Patent, is

1. In a. tool of the class described, a hollow inner shaft, a hollow outer shaft rotatable on said inner shaft, an abrading element rotatable with said outer shaft, a work engaging pilot member ada ted to extend into an end of said inner sha for centering the same with respect to the work, means for driving said outer shaft, and means for axially adjusting said outer shaft and abrading member toward or away from the work, said means including a part extending into the end of said inner shaft away from said pilot member, and adapted to engage said member.

2. In a tool of the class described, a support having a tubular part projecting therefrom, a shaft rotatable on said part, a grin-ding wheel carried by the shaft at its outer end, a pilot member and support for engaging the work and projecting into the outer end of said tubular part to center the grinding wheel with respect to the work, a rod extending into the opposite end of said tubular part and adapted to have end abutment against the pilot and supporting member, and means for adjustably clamping the rod and operable in connection with said first means to axially adjust the rod to effect 9. raising or lowering of the first means, shaft and wheel with respect to the pilot and supporting member.

3. In combination, a motor frame having a part projecting axially therefrom, an armature shaft encircling the frame part, a grinding member carried by the shaft, and a member stationary with respect to the work to be ground and co-acting with the frame part to center the grinding member with respect to-the work.

4. In combination, a motor the frame of which has a part projecting therefrom, a shaft driven by the motor in concentric relation to said frame part, a grinding member carried by the shaft, and a stationary member detachably carried by the work and co-acting with the motor frame part to center the shaftand grinding wheel with respect to the work.

5. In combination, a motor the frame of which has a part projecting therefrom, a motor driven shaft concentric to said part, agrinding wheel carried by the'shaft, means adapted to be carried by the work to. engage the frame part and center the grinding wheel with respect to the work, and means carried by the motor frame and operable in 000 ration with said first means to axially adjust the grinding wheel with respect to the work.

6. In combination, a motor, a sleeve attached to and projecting from the motor, a

shaft encircling the sleeve and driven by the motor, a grinding member carried by the Having thus described my invention,what I shaft, a support adapted to be carried by the work and to engage the sleeve to center the grinding member with respect to the work, and a manually operable control carried by the motor and working through the sleeve in co-action with the support to adjust the grinding member with respect to the work.

7. A valve seat grinding tool having a motor, a sleeve fixed to and projecting from the motor frame, a hollow shaft encircling the sleeve and driven by the motor, a grinding member carried by the shaft, a support adapted to 'detachably project from the, work and to enter the sleeve to hold the grinding member concentric to the surface to be ground, a control rod projecting into the opposite end of the sleeve adapted to, abut against the support, and means connecting the rod and motor frame and adjustable to effect a raising and lowering of the motor, shaft, sleeve and grinding memher with respect to the support and work.

8. Valve grinding mechanism comprising a motor frame, a stationary tubular shaft secured to the frame'and projecting therefrom, a driven shaft rotatable on said stationary shaft, a working tool operatively connected to the end portion of said driven shaft, a pilot extending into the bore of said stationary shaft for positioning the working tool relative to the work, and means engaging the end of said pilot for adjusting the position of said tool with respect to the work. 9. Valve grinding mechanism comprising a motor, a tubular shaft driven by said mo-' tor and projecting therefrom, a working tool carried by said shaft, a pilot extending into said shaft adjacent said tool, and means adjustable from the opposite side of the motor and cooperating with said pilot forvarying the operative position of the tool relative to the work.

10. In a tool of the class described, a hollow non-rotatable shaft, a hollow rotatable shaft mounted on said first shaft and adapted to have axial movements therewith, an abrading element carried by the rotatable shaft, a work engaging pilot adapted to engage said first shaftto center it' with re-- ing a rotation of the rotatable shaft to axially adjust the two shafts and abrading member inwardly and outwardly with respect to the work.

11. In a tool of the classdescribed, inner and outer hollow shafts axially movable together and mounted one on the other for free relative rotary movements, an abrading element carried by the outer shaft, a work engaging pilot adapted to have work centering connection with one of said shafts, and means connecting the pilot and outer shaft through the inner shaft and operable in cooperation with the pilot during a running of the outer shaft to axially adjust the shafts and abrading element toward or away from the work.

12. In a tool of the class described, inner and outer hollow shafts axially movable to gether and mounted one on the other for free relative rotary movements, an abrading element carried by the outer shaft 'at one end thereof, a work engaging pilot adapted to have work centering connection with one of said shafts, and means connecting the pilot and one of said shafts through the inner shaft and operable in cooperation with the pilot during a running of the outer shaft to effect a posltive axial adjustment of the shafts and abrading element toward or away from the work, said means being manually adjustable from the opposite end of-the outer shaft to that which-carries the abrading element.

In testimony whereof I I vhave hereunto signed my name to this specification.

ERNEST A. HALL.

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